BY GAIL GLADSTONE and CHRIS BARTER

More than two years ago, heavy rains fell on a June day in Acadia National Park. On Sargent Mountain’s South Ridge, the rain rushed down the bare granite, gathering force as it funneled into the narrow gorge below – and through Maple Spring Trail.

The water tore up stone steps and paving, bulldozed retaining walls, and swept away soil, destroying a quarter-mile section of the historic trail – from the Hemlock Bridge to the intersection of the Giant Slide Trail.

Due to the extent of damage, the trail was closed for nearly two years while the park determined the trail’s future. And this summer, Acadia’s trail crew has been hard at work putting the Maple Spring Trail back together.

Navigating exactly how to accomplish that feat is the work of an interdisciplinary team of park staff. Their approach to trail rehabilitation incorporates adaptive management and uses the Resist-Accept-Direct (RAD) Framework, which serves as a guide to adaptative responses to different possible climate-change scenarios.

Originally built in 1871 as an ascent up Sargent’s South Ridge, the Maple Spring Trail follows along a stream and through the gorge between Gilmore Peak and Sargent Mountain. The trail gives its hikers the unique experience of tracking the floor of a steep stone gorge, conveying the presence and power of local geologic history, and it offers access to a diversity of natural features, including views of cascades through the gorge and Pulpit Rock.

The stone steps, rubble retaining walls, and patio stone paving are important historic features of Maple Spring Trail, making it a valuable part of the larger historic trail system on Mount Desert Island, which is listed in the National Register of Historic Places.

Left: Damaged section of Maple Spring Trail near the Hemlock Bridge after an early June 2021 rainstorm. (Photo by Ashley L. Conti/Friends of Acadia). Right: Damage to a foot bridge on the Maple Spring Trail. (Photo by: Ashley L. Conti/Friends of Acadia)

During a workshop in November 2021, park staff, partners, and stakeholders discussed a range of management options for the Maple Spring Trail in the context of a changing environment.

The Resist-Accept-Direct (RAD) framework asks resource managers to assess a range of possible options: resisting change with concerted intervention, accepting change and allowing “nature to take its course,” or directing change with management that works in tandem with predicted environmental changes. RAD also takes into account each approach’s feasibility, cost, and longevity.

For the Maple Spring Trail, planning for a full restoration of the destroyed stonework would resist the predicted climate – namely, more high-intensity storms. It would be extremely labor intensive with the potential for more heartbreak should all be lost again in a similar storm.

To reroute the trail out of the stream corridor is a response at the other extreme; it would preserve the existence of the trail, but the historic context would be completely lost.

Following that initial workshop, Acadia’s trail crew made several site visits to hash out the practical solutions and decide on a specific plan. As thoughts evolved from theory to design, trails staff met with the rest of the park team to discuss the important goals that were not always simultaneously achievable: construction sustainability, protection of water quality, protection of the natural environs, visitor enjoyment (i.e., the “hike-ability” of the trail), and preservation or reconstruction of historical features. These discussions continued nearly up until the start of work in August 2023.

rail crew install the new bridge over
Maple Spring. (Photo courtesy Gail Gladstone)

Landing on a rehabilitation approach that worked well for the entire quarter-mile section proved understandably challenging. But as the trail crew focused on specific trail features, solutions became more obvious. For instance, an intact section of historic stonework still led to the site of an historic bridge crossing. The challenge became figuring out how the trail could pass through this intact section.

Design iterations of the bridge led to the replacement of the historic crossing with a taller, stouter bridge to allow increased water flows to pass under it, while protecting the stream bank from scour where its abutments would be built. Leading up to the bigger bridge is now a combination of stone and rustic wood steps, and a section of elevated boardwalk connects the new bridge to a stable area on the old route where new stone paving can be trusted to last.

ACADIA NATIONAL PARK TRAILS FOREMAN Dave Schlag removes the strapping
from the highline cable hook used to carry poles to the worksite during
the construction of a new footbridge over Maple Spring. (Photo by Julia Walker Thomas)

Other solutions were applied using this feature-by-feature approach. A new short bridge now connects intact pieces of historic stone paving. In an area 50 feet downstream of the original crossing, a new section of stepping stones is planned that utilizes two large stones in the stream that have already withstood previous storm events.

In another area where the stream bank and trail have been completely undermined, the trail moves about twenty feet up the bank where it is built as a cut-in slope on more secure ground. It then reconnects to the existing trail a hundred feet further on. In still another area, a section of destroyed stone paving was abandoned and a steel handrail is added along a cliff to give hikers sure passage on the narrow piece of bedrock that remains.

In rebuilding the trail in a way that we hope will last, Acadia’s trail crew was able to use nearly every piece of remaining historic trail, avoid lengthy reroutes, and provide the same overall dramatic visitor experience.

These decisions embrace the complexity of the RAD framework—resisting, accepting, and directing change for specific trail features – all within one small section of trail. Where the stream’s power seemed less destructive, the park chose to rebuild. Where total restoration was too risky for catastrophic loss, the park accepted and moved the trail or changed techniques. Building with wood accepts that whatever is built may periodically be damaged from storm events and need to be replaced.

Ultimately, the park made decisions towards a future, more stable state.

When the Maple Spring Trail work is complete, those looking closely will find a host of trail solutions on display: stonework, woodwork, cut-in slope bench cuts, riprap, and steel rail.

There is no perfect solution in the era of climate change, but on the Maple Spring Trail, those seeking the experience of hiking through a dramatic gorge on hand-crafted stonework and rustic wooden bridges will find that the Acadia style endures.

Retired Acadia National Park Trails Foreman Gary Stellpflug, left, and Acadia National Park Trails Foreman David Schlag uses a highline to construct a new footbridge over Maple Spring. (Photo by Julia Walker Thomas/Friends of Acadia)

Chris Barter is Acadia National Park’s Trail Crew Supervisor and Gail Gladstone its Cultural Resource Program Manager.